Glycemic Index and Glycemic Load: What Is It and How To Use It

Glycemic index (GI) and glycemic load (GL) are two concepts used to measure how quickly and how much a carbohydrate-containing food raises blood sugar levels after consumption. These concepts are particularly important for people with diabetes or those looking to manage their blood sugar levels.

1. Glycemic Index (GI):

The glycemic index is a numerical scale that ranks carbohydrates based on how quickly they cause a rise in blood glucose levels when compared to a reference food, usually glucose or white bread. The scale ranges from 0 to 100, with higher values indicating a faster and larger increase in blood sugar levels. Foods with a high GI are rapidly digested and absorbed, causing a rapid spike in blood sugar, while foods with a low GI are digested and absorbed more slowly, resulting in a more gradual and moderate increase in blood sugar.

– Low GI Foods: These foods have a GI value of 55 or less. They are digested and absorbed slowly, leading to a slower and more sustained rise in blood sugar levels. Examples include most vegetables, whole grains, legumes, and fruits like berries and apples.

– Medium GI Foods: These foods have a GI value between 56 and 69. They have a moderate effect on blood sugar levels. Examples include some fruits, whole wheat products, and basmati rice.

– High GI Foods: These foods have a GI value of 70 or more. They cause a rapid and significant spike in blood sugar levels. Examples include white bread, sugary cereals, candy, and sugary beverages.

2. Glycemic Load (GL):

The glycemic load takes into account both the glycemic index of a food and the amount of carbohydrates in a typical serving of that food. It provides a more practical measure of a food’s impact on blood sugar levels because it considers both the quality and quantity of carbohydrates consumed.

The formula to calculate glycemic load is:
GL = (GI × Carbohydrate content in grams) / 100

– Low GL: A value of 10 or less is considered low and is less likely to cause significant blood sugar spikes.

– Medium GL: A value between 11 and 19 is considered medium.

– High GL: A value of 20 or more is considered high and may lead to a substantial increase in blood sugar levels.

GI and GL Food Chart
Here’s a simplified glycemic index (GI) food chart that provides examples of different foods and their corresponding GI values.

Low GI Foods (55 or less):

– Legumes (beans, lentils, chickpeas)

– Non-starchy vegetables (broccoli, spinach, peppers)

– Whole grains (oats, barley, quinoa)

– Most fruits (apples, pears, oranges, berries)

– Nuts and seeds

Medium GI Foods (56-69):

– Whole wheat products (bread, pasta)

– Basmati rice

– Sweet potatoes

– Corn

– Pineapple

High GI Foods (70 or more):

– White bread

– White rice

– Potato chips

– Sugary breakfast cereals

– Watermelon

– Dates

Low GI and Low GL Foods:

• Green vegetables (spinach, lettuce, kale)
• Non-starchy vegetables (broccoli, cauliflower, zucchini)
• Legumes (lentils, chickpeas, kidney beans)
• Whole grains (oats, barley, quinoa)
• Berries (strawberries, blueberries, raspberries)
• Nuts and seeds

Medium GI and Medium GL Foods:

• Whole wheat bread
• Brown rice
• Whole grain pasta
• Sweet potatoes
• Corn on the cob
• Grapes
• Mangoes

High GI and High GL Foods:

• White bread
• White rice
• Cornflakes
• Potato chips
• Watermelon
• Dates
• Pineapple

It’s important to note that the glycemic index and glycemic load of a food can be influenced by various factors, including ripeness, cooking method, processing, and the presence of other nutrients (such as fiber, fat, and protein) in the food. When planning meals, consider not only the GI and GL of individual foods but also the overall balance of nutrients and portion sizes. Combining carbohydrates with protein, healthy fats, and fiber can help mitigate the blood sugar response to high-GI foods. If you’re managing a specific health condition like diabetes, it’s recommended to work with a healthcare professional or registered dietitian to create a personalized dietary plan.

For a more complete chart of glycemic index foods, please click here.